Firearms vary in barrel length. Typically the longer the barrel the longer the sight radius and the more muzzle velocity you get from the propellant. However, the longer that the barrel is the longer the slide tends to be; and, all else being equal, the more barrel heavy and less balanced the firearm is. As a good example, the Glock 19 has a short barrel and weighs about 23 ounces. In contrast, a Glock 17L has a long six inch barrel and a commensurately long slide. To lighten the muzzle, a port about 2.25″ in length is created just behind the front sight by removing a rectangular piece of steel thereby reducing the overall weight of the Glock 17L to 26-27 ounces and rebalancing the weapon so that it is not as barrel heavy.
Having one or more ports cut from the slide to reduce overall weight and to reduce barrel heaviness is an acceptable configuration in a relatively clean and safe firing environment, such as a competition or a well maintained range. However, in the field or in combat, the lightening port is an open access for water, dirt and debris to enter the slide and cause damage or outright malfunction. Thus, the Army's standard issue pistol is a shorter barrel Glock 19 with a slide that does not need a lightening port. The Army has decided to opt for shorter slides with shorter sight radii, faster draw and slower muzzle velocity over the long slide models having better accuracy and muzzle velocity. Hence, there is a need for a method or device to plug the lightening ports of the more accurate long slide firearms to prevent the entrance of dirt and debris without recreating a barrel heavy side arm. Although the concepts herein are described in the context of a Glock 9 mm semi-automatic pistol, such discussion is exemplary only for brevity and clarity and should not be understood to be limited to that particular make, model or type of weapon. The concepts discussed herein may be applicable to other makes and models of side arms as well as long guns and other larger weapons. As additional examples, the Springfield Armory XDM 5.25 and 1911-A1 Longslide also have lightening ports as does the Salient Arms Dragonfly CNC Aluminum aftermarket slide.